Dynamic DMCL: You can use a DCMT command to load a new copy of the DMCL load module without recycling the DC/UCF system.

Document ID : KB000054000
Last Modified Date : 14/02/2018
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Description

By using the dynamic DMCL feature, you make a modified DMCL available under central version without having to bring down and restart the DC/UCF system.

Solution

You can use a DCMT command to load a new copy of the DMCL load module without recycling the DC/UCF system.

You can dynamically:

  • Add or remove a segment, area, or file.
  • Add or remove a buffer pool.
  • reassign files to buffers
  • change file dataset name
  • Expand an area by:

    - Increasing the page range.
    - Increasing the page size.
    - Adding new files.

To safeguard the dynamic process, CA IDMS/DB quiesces affected areas, as appropriate, and updates the journal header with the timestamp of the new DMCL.

By using the dynamic DMCL feature, you make a modified DMCL available under central version without having to bring down and restart the DC/UCF system.

Example: In this example an EXPAND PAGE operation has been done for area ORG-DEMO-REGION, the file has been assigned to a different buffer and the file DSName has been changed. The AREA and FILE definitions are altered and the DMCL is then generated, punched and linked into the DBA loadlib.
When the command DCMT V DMCL NC is issued, IDMS loads the DMCL load module, determines what has changed, and displays those changes. It then prompts for a YES or NO response to proceed with the changes or cancel the new copy operation.

Here is what the DBA would see on the terminal after issuing DCMT V DMCL NC:

     DMCL changes.... R160DMCL Compile Date/Time: 2009-04-20-08.09.22.9088        
     Overall changes....                                                          
                                                                             
                                                                             
     ** Area     EMPDEMO.ORG-DEMO-REGION                     changed              
     ** File         EMPDEMO.ORGDEMO                         changed              
                                                                             
     Detail changes....                                                           
                                                                             
                                                                             
     ---------- Area -----------   Lock    Lo-Page    Hi-Page #Ret  #Upd #Tret #Nt
     EMPDEMO.ORG-DEMO-REGION        Upd      75151      75175    0     0     0   
                      Calc-Pg    Pg-Size SMP-Intrvl   -DDname-         
                       75175       4276       2122   ORGDEMO          
       Changing to...              5064                               
                                                                            
                                                                            
     -------- Data File --------  # Pages  Pg-Size  Fl-Type M-Cache S-Cache      
     EMPDEMO.ORGDEMO                   25    4276  non-VSAM    No      No        
               Changing to...                5064                                
     Buffer name:  EMPWBUFFER           changed to BCBWBUFFER                    
     DDname: ORGDEMO    DSname (DMCL)..MEN.C5100.PHILTEST.EMPDEMO.ORGDEMO.P4276        
     DDname: ORGDEMO    DSname (JCL)?  Not Allocated                             
     Change                            MEN.C5100.PHILTEST.EMPDEMO.ORGDEMO.P5064
                                                                            
                                                                            
     Continue with VARY DMCL, Yes or No?
 
On the IDMS Log these messages were produced:
 
DC260100 V1600 USER:userid   DCMT      V DMCL NC                      
DC200084 V1600 T293 EMPDEMO.ORG-DEMO-REGION Area Varied Offline  
DC200084 V1600 T293 EMPDEMO.ORG-DEMO-REGION Area Varied Close    
DC205003 V1600 T293 Disk Journal is FULL.  Submit ARCHIVE JOURNAL
DC200084 V1600 T293 EMPDEMO.ORG-DEMO-REGION Area Varied Update